WWII 4671 ACORN VALVE

Acorn 955 Triode 1934 followed by 954 and 956 Pentode

The Valve known as an Acorn, was one of the fist truly miniature valves and was used in Military equipment during WW2. In the 1930's RCA produced the Acorn valves consisting of a 955 Triode in 1934 followed by the 954 Pentode in 1935 and.variable-mu pentode 956, in 1936.
With an upper working frequency of 400Mhz these valves were mass produced in the USA during the Second World War for a lot of electronic equipment and a large number were imported into the UK.
These valves were not used in Proximity shell fuses, simply not robust enough.

Your comments:

• Still have a Grid Dip Meter using this tube. Also have a stock of them. Back in the late 1947's a friend and I went to Radio Row in New York City to buy some form of WWII Surplus communication radio. Not having mush money we wound up with two nice polished wood comm. boxes in the VHF or UHF bands. They contained the acorn tubes. Didn't work well and had terrible micro phonics when the radios were touched.
  .......... Bob Ziolkowski, Apopka FL, 2nd of January 2015
  
  
• In the 1960s I got hold of a couple of theses and used the as the basis of a T.R.F shortwave receiver with 2 RF stages.This used commercially avaiable plugin coils,which were changed for different bands.I remember it worked really well.unfortunately no digrams or photos have survived many house moves including a change of country.I bought the valves from a goverenmemt and military service dealer in Durban (South Africa)
  .......... Davis R Holmes, Worcester, 8th of June 2011
  
  

A0620